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Combined Antiplatelet and Anticoagulant Therapy Decreases Rate of Thrombosis and Prolongs Time to Recurrence in Patients with Antiphospholipid Syndrome
March 10, 2017-Hong Kong, China — Combined antiplatelet and anticoagulant therapy forpatients with antiphospholipid syndrome presenting with arterial events, vs antiplatelet oranticoagulant therapy alone, may prolong time to thrombosis and overall decrease thrombosisrecurrence significantly.
This preliminary finding of a retrospective database analysis was reported at the 58th AnnualMeeting of the American Society of Hematology, from December 3 – 6.
Maria Teresa DeSancho, MD, MSc, of Weill Cornell Medical College, New York, explained thatthe management of patients with antiphospholipid syndrome presenting with arterial thrombosisremains controversial.
“I often see relatively young patients with antiphospholipid syndrome in my practice,” she said.“They present with arterial thrombosis, mostly stroke or transient ischaemic attack. It is difficultto tell a young patient that he or she needs to commit to taking blood thinners for the long term.It is much easier to take aspirin instead.”
No prospective studies have demonstrated the superiority of high- over moderate-intensityanticoagulation with vitamin K antagonists over antiplatelet agents.
The Antiphospholipid Antibodies and Stroke Study showed that, among patients with ischaemicstroke, the lupus anticoagulant or anticardiolipin antibodies did not predict either increased riskof subsequent vascular occlusive events over 2 years or a distinct response to aspirin or vitaminK antagonists.
Dr DeSancho and colleagues set out to evaluate recurrent thrombosis in patients withantiphospholipid syndrome presenting with arterial thrombosis that were treated with eitherantiplatelet and/or anticoagulant therapy.
Using a single-center and a multicenter antiphospholipid antibody database, Dr. DeSancho and coinvestigators collected demographic and clinical data of patients with antiphospholipidsyndrome who presented with arterial thrombosis.Evaluated data included gender; age; ethnicity; cardiovascular risk factors (hypertension,smoking, hyperlipidaemia, diabetes, and family history of early cardiovascular disease); type ofantiphospholipid antibodies; and treatment modalities (antiplatelet and/or anticoagulant).Cardiovascular risk factors were available only for patients seen at the single center.
The primary outcome was rate of thrombosis and time to thrombosis recurrence. Kaplan-Meiercurves were used to estimate the time at which one fifth of patients were expected to suffer asecond thrombosis.
A total of 139 patients was identified, 92 (66.2%) of whom were females. Median patient agewas 42 (range 18 - 84) years.
The majority of patients [n=85 (61.2%)] were Caucasian, 19 (13.7%) were Hispanic, 13 (9.4%)were Asian, six (4.3%) were black, and one (0.7%) was Middle Eastern. Median follow-up timefrom initial thrombosis was 4.24 years.
Thirtyseven (27.3%) patients were treated with anticoagulants, 43 (30.9%) with antiplateletagents, and 58 (41.7%) with a combination of both.
Median age at initial thrombosis was 37, 46, and 42 for the anticoagulant, antiplatelet, andcombined therapies, respectively.
The median number of cardiovascular risk factors and the presence of triple positivity for theantiphospholipid antibodies were similar in the three groups.
Initial thromboses were observed in cardiac, cerebral, and other arteries with cerebral thrombosisbeing the most common clinical manifestation. The only major difference across groups was inpatients presenting with coronary artery events, who were more likely taking antiplatelet agents.
Overall, 29 patients had a recurrent thrombotic event with 9 (23.7%) in the anticoagulant, 16(37.2%) in the antiplatelet, and 4 (6.9%) in the combination therapy group. Overall, the timeestimated for 20% of patients to experience recurrent thrombosis was 3.4, 7,3 and 16.3 years forpatients in the antiplatelet, anticoagulant, and combined therapy respectively.
Compared to those on anticoagulants, the hazard ratio of patients on antiplatelet medications was2.1-fold higher, however though due to low power, the difference was marginally significant(95% confidence interval 0.90, 4.7, P = .09).
Those on combination therapy were at a 70% lower hazard of a recurrent event (hazard ratio0.30; 95% confidence interval 0.08, 0.83; P < .025).
Dr DeSancho concluded that combined antiplatelet and anticoagulation therapy for patients withantiphospholipid syndrome presenting with arterial events, vs antiplatelet or anticoagulanttherapy alone, may decrease rate of thrombosis and prolong the time to thrombosis recurrence.
“It appears that using both an anticoagulant plus an antiplatelet agent is superior,” she said. “The results need to be taken with caution, however, since this was a retrospective study and we donot have information regarding compliance with either treatment.”
She added, “The ideal scenario will be to design a multicentre, randomised, controlledcomparison of dual antithrombotic therapy (warfarin international normalised ratio 2 - 3) +aspirin 81 mg vs anticoagulation with warfarin alone (international normalised ratio 2 -3). It willbe important to make sure that the international normalised ratio is maintained in the therapeutic range.”